1. Field of the Invention
The invention relates to a liquid crystal display, and more particularly, to a liquid crystal display having two subpixels with two different tilt directions of the LC molecules and two different luminances per color pixel.
2. Description of the Related Art
A liquid crystal display (LCD) is one of the most widely used flat panel displays. An LCD includes two panels (e.g., two substrates, having field-generating electrodes such as pixel electrodes and a common electrode) having polarizing filters and a liquid crystal (LC) layer interposed therebetween. The LCD displays images by applying voltages to the field-generating electrodes to generate an electric field across the LC layer, which determines orientations of LC molecules in the LC layer to adjust the polarization of incident light. The liquid crystal twists the polarization of light entering one filter to allow it to pass through the other filter.
The LCD further includes a plurality of thin film transistors (TFTs) connected to the pixel electrodes, and a plurality of signal lines connected to the TFTs and transmitting signals to the TFTs.
Among the various types of LCD displays, there is a vertical alignment (VA) mode LCD, which aligns LC molecules such that the long axes of the LC molecules are perpendicular to the panels in absence of electric field, is preferred because of its high contrast ratio and wide reference viewing angle.
The wide viewing angle of the VA mode LCD can be realized by providing cutouts in the field-generating electrodes and protrusions on the field-generating electrodes. Since the cutouts and the protrusions can determine the tilt directions of the LC molecules, the tilt directions of LC molecules can be distributed into several directions by designing the cutouts and the protrusions such that the reference viewing angle is widened.
However, the VA mode LCD has poor lateral visibility as compared with frontal visibility. For example, a lateral gamma curve is different from a frontal gamma curve.
In addition, the arrangement of LC molecules may be distorted due to the height difference caused by the signal lines, causing light leakage, thereby decreasing the contrast ratio.